Self-hardening water-glass compositions



Patented Dec. 8, 1953 U E'I E LS SELF-HARDENING WATER-GLASS COMPOSITIONS (Cl. 106- 74).v

7 Claims;

The present invention relates tov-self hardening water-glass. compositions yielding acidproof masses, to a process of' preparing said compositions; and to means for carrying out said process.

For constructions which are to be resistant to acids, self-hardening water-glass cements are used-to a large'extent; their hardening being effected by salts offiuosilicic acid or analogous complex fluorine compounds contained in the cement powders; As compared with the waterglass cements, which are not self-hardening; theseproducts offer" considerable advantages in practice, specially byspeeding up constructional work."

For some uses, however; the'c'ements contain ing= fluorine compounds are not entirely satis-- factory in all cases.- For instance, in the case' of cement-work in contact with chrome-nickel steels or lead, the presence of fluorine compounds in the cement'causes the metals and metal alloys to corrode wherebyconsiderable deterioration maysometimes occur; In a similar way; the presence. of. fluorine compounds inter feresswith. processesin which corrosive. liquids are circulated and hydrofluoric acid solutions which are thereby, formed, although they may.

be dilute, they gradually. corrode the: masonrybuilt up, with the-useof said cements.

The: present invention is based on the ob'ser vationithat halogen-free, self-hardeningiwaterglass compositions yielding; acid-proof masses may be obtained which do not exhibit the above disadvantages and which'mayv be used with special advantage for the purposes mentioned above. The compositions according to the invention yield satisfactory, chemically stable cement-work especially when in contact with chrome-nickel steels orlead. The-corrosionof stone-material which occurs in some casesby'the 4O useofcements containing fluorine compounds is entirely avoided. Further advantages are a} noteworthy impermeability to liquids, a goodswelling capacity; which is useful for certain purposes, and a greatly increased power of' adhesion of the cement-work to acid-proof ofwsioz to rho-higher than about 10.35, and of T potassium silicate solutions having a ratio of" SiOz to K20 less -than--about-2L-25 and a ratio" of SiO2 tO-I-IQGhi-gherthan about 0135'," an inert" filler and as hardener to react with the alkali constituent of the wa'ter glass solution; at least one member oi the group consisting of esters; amids,-- and anhyd'ride's of aliphatic organic acids.

The range 5 of the alkali water-glass someoneused is limitechon the one halid} bythe a above mentioned ratios and, on the other hand; by their viscositywhich is lflot' higher-thah about600 centip'oi-sesat' 20 'C; With sodium silicate solu-' tions" the ratid or siOz' 'to NaO P may advanta' geously be abo'ut 2k5 or even les'sg' fon instance about 137 2 and with-potassium: water -gl'ass solutionsthe: ratio of Si-Oz to K20 may be advan t'a'geously about 219; or -"even les's;- for instance about 1-.64: The" ratio-Of SiO'Z totiI-EO is'always higher than about 0135.

some casesfit may 'be ofadvantage'to "use mixtures: of sodium -sili'catand potassium sili-' ca te solutions; the proportionso'fthe two'w'a'ter glass" solutions oneto: the 4 other varying-r within wide a limits; Thus; forfinstance; mixtures may, be used -in 'which t ratio of the tw'o' soluti'on's is 1 1: However? one or the 5? other constituent may also predorr'iinat ahd th'e ra'fid ma'y hue-" 23; figure between about -l zz and 2': Lor even higher."

fi11er'sthere-are used the usua nert-substances, for instance quartz sanda'n qu-art'z powder. Besides-the "e silb'st'ances',--- oth'er" silicate powders-such" as glass-powdfi porcelain powder, chamott owd'er 'and 'stonewar pow er mayme usedf In certain cases; fillers having a*- go d thermal condu'c y;" such as naturalor artifi cial graphite, for instance of tli' k-ifiduse'd for carbonelectrodes; silicon carbidesilicon'or-the' like, are-advantageous] Sometimes; mixtiires of difierent fillers also -givesatisfactoi-'y'*rsults;

m-sorr e casesit'may hie-suitable to add "otner' solid substances, as'ffon'instancei Kieselweiss (active silicic acid), i. e. a"silicic"afcid havinga particularlyhi'gli' reactivity"with alkali ly'eseve'n m'the"cold: r

Especially suitable'hardening agents reestrs;

such as glycol di-rormate and glycer'oltri forin ateandalsoiesters 'of"pol'yba'sic "a ds', chas oxalic'acidfdimethyl esters: and: esters orhydfoxr acids, such" as"'citric"acid" trimethyl ester," also including internal"esterssficn' as "glycolid'e, advantageouslyma. 'polyniriid' 'forrfi. Aniids 0f aliphatic. organic acids-,--su,ch-as formamide'ox amide, .triacetaniidei 'and mamnamid," and also anhydridesil tor instance su'ec'mic anh'yafiae; ni'aleic anhydrid or"'thelik'e'ar also suitable Equivalent weight: Glycolide 58 Oxalic acid dimethyl ester 59 Glycol di-formate 59 Glycerol tri-formate 58.6 Formamide Oxamide 44 Triacetamide 47 Malonamide 51 Succinic anhydride Maleic anhydride 49 The substances of this kind which are solid at ordinary temperature are best used as powders. There enter into consideration, for instance: glycolide, especially in the polymerized state, oxalic dimethyl ester, oxamide, tri-acetamide, malonamide, succinic anhydride, maleic anhydride or the like.

Liquid products of the said kind may, however, also be used, especially those boiling above 100 C. as, for instance: glycol di-formate, glycerol tri-formate, formamide or the like.

In most cases, a small quantity of a hardener is sufficient, for instance a total quantity of about 1 per cent. to about 5 per cent, calculated on the weight of the filler. In particular cases, lower or higher percentages may also be used.

In practice, such compositions have proved to be especially suitable as contain as hardener glycolide in any molecular state, for instance in the polymerized state, it being advantageous in some cases to use a filler with a good thermal conductivity such as graphite. For obtaining a special effect, part of the glycolide can be replaced by an amide of an aliphatic organic acid such as formamide. In all cases, an addition of Kieselweiss (active silicic acid) has proved advantageous.

The compositionsaccording to the present invention are advantageously prepared by first mixing the ingredients mentioned above, 1. e. the filler, the hardener, and the other solid substances, if any, and then cementing this mixture with an alkali water-glass solution of the above mentioned kind. For instance, one mixes glycolide, preferably in the polymerized state, and a filler, if desired with addition of formamide and/or active silicic acid and cements this mixture with an alkali water-glass solution of the above mentioned kind.

Shortly after the cementingafter about hourthe composition begins to harden to an acid-proof mass. The hardening is finished after some days.

Reaction takes place, between the hardeners and the water-glass solutions of the above mentioned kind, in such a way that the alkali of the water-glass solution used is neutralized and the silicic acid thus precipitated serves as a binding a ent.

The quantity of the alkali water-glass solution in proportion to the mixture comprising the filler and the hardener, depends upon the kind 4 and quantity of the individual constituents used and may vary within wide limits. It has been found that, for instance, suitable masses are obtained by using for 100 g. of a mixture comprising a filler and a hardener, about 25 to 30 cc. of an alkali water-glass solution of the above mentioned kind. In certain cases, these values may be lower or higher.

For carrying out the process it may be of particular advantage to use a means which comprises two separately packed preparations suitable for being mixed together to produce the self-hardening composition,

one or more aforesaid derivatives of aliphatic organic acids serving as hardener, and, if desired, another solid substance or substances, for

instance active silicic acid, and the other preparation consisting of an alkali water-glass solution of the kind described.

The following examples serve to illustrate the invention but they are not intended to limit it thereto, the parts being by weight:

Example 1 parts of quartz powder of suitable fineness of grain, with a residue of 10-25 per cent on a 10,000 mesh sieve, 4 parts of clay and 2.5 parts of an active silicic acid, i. e. a silicic acid of an especially high reactivity with alkali lyes even in the cold, are mixed with 3.5 parts of glycolide. g. of this cement powder are mixed with 30 cc. of a potassium silicate solution in which the ratio of $102 to K20 is about 1.64 and that of $102 to 520 is about 0.46. The viscosity of the water-glass solution is 80 centipoises at 20 C. After about 20 minutes, the composition begins to harden and at ordinary temperature the setting is completed after 3 days.

Example 2 A cement powder consisting of 92 parts of quartz powder of suitable fineness of grain and 4 parts of kaolin are mixed with 4 parts of oxalic dimethyl ester. 100 g. of this cement powder are treated with 30 cc. of a sodium silicate solution in which the ratio of SiOz to NazO is about 1.72 and that of Si'Oz to H2O is about 0.43. The viscosity of the water-glass solution amounts to 450 centipoises at 20 C. After about 30 minutes, the composition begins to harden and the setting is complete after 3 days.

Example 3 1 part of glycolide, advantageously in the polymerized state, 3 parts of formamide, 4 parts of Kieselweiss (natural fine siliceous sinter) 46 parts of fine quartz sand and 46 parts of very fine quartz powder are mixed together. 100 g. of this mixture are cemented with 30 cc. of a sodium silicate solution in which the ratio of S102 to NaaO is about 2.55 and that of SiOz to H2O is about 0.55 and which has a specific gravity of 1.48 and a viscosity of 350 centipoises at 20 C. The composition begins to harden after 30 minutes and finally yields an acid-proof mortar impermeable to liquids and having a resistance to pressure of about 300 kg./cm.

Example 4 A mixture of 1 part of glycolide, which may be in a polymerized state, and 3 parts of formamide are mixed with 6 parts of Kieselweiss (active one preparation consisting of a powder containing the filler, the

'silicic acid) and 90 parts of a quartz powder of such a fineness of grain as is adapted to the particular requirements. 100 g. of this mixture are cemented with 25 cc. of a potassium silicate solution in which the ratio of S102 to K is about 2.1 and that of SiOz to H2O is about 0.37. The viscosity of the water-glass solution amounts to 50fcentipoises at 20 C. The composition begins to harden after minutes. After 8 days, the hardened composition has a resistance topres- 'e'sure of 250 ksJcmfi.

Example 5 A mixture is prepared from 4 parts of succinic anhydride and 96 parts of artificial graphite, 100 g. of this mixture are cemented with 40 cc. of a sodium silicate solution in which the ratio of S102 to NazO is about 2.0 and that of SiOz to H2O is about 0.50. The viscosity of the sodium silicate solution amounts to 550 centipoises at 20 C. The composition obtained begins to harden after about minutes and the setting is finished after about 4 days.

Example 6 A mixture is prepared from 1 part of glycerol triformate, 2 parts of maleic anhydride, 47 parts of natural raphite and 47 parts of very fine glass powder and 3 parts of active silicic acid, for instance Kieselweiss. 100 g. of this mixture are cemented, shortly before use, with 22 cc. of a potassium silicate solution in which the ratio of SiO2 to K20 is about 1.75 and that of Si20 to H2O is about 0.39. The potassium silicate solution has a viscosity of 60 centipoises at 20 C. After about minutes, the composition begins to harden and after about 3 days the setting is complete.

I claim:

1. A self-hardening composition including a solid constituent and an aqueous water-glass constituent capable of yielding, upon hardening, a chemically-stable acid-resistant solid, wherein said solid constituent comprises an inert filler and 1-5% of glycolide, and said water-glass constituent is selected from the group which consists of sodium silicate solutions having a ratio of SiO2 to Na2O less than about 2.75 and a ratio of SiOz to H2O higher than about 0.35, and potassium silicate solutions having a ratio of S102 to K20 less than about 2.25 and a ratio of SiO2 to H2O higher than about 0.35, the amount of said water-glass constituent ranging from about 25 cubic centimeters to about 30 cubic centimeters per 100 grams of solid constituent present in said composition.

2. A self-hardening composition including a solid constituent and an aqueous water-glass constituent capable of yielding, upon hardening, a chemically-stable acid-resistant solid, wherein said solid constituent comprises inert filler and 1-5% of polymerized glycolide, and said waterglass constituent is selected from the group which consists of sodium silicate solutions having a rat o of SiO2 to NazO less than about 2.75 and a ratio of SiO2 to H2O higher than about 0.35, and potassium silicate solutions having a ratio of S O2 to K20 less than about 2.25 and a ratio of S102 to H2O higher than about 0.35, the amount of said water-glass constituent ranging from about 25 cubic centimeters to about 30 cubic centimeters per 100 grams of solid constituent present in said composition.

3. A self-hardening composition including a solid constituent and an aqueous water-glass constituent capable of yielding, upon hardening, a

6- chemically-stable acidaesistarit solid, wherein said solid constituent comprises an inert filler and 1-5% of glycolide and less than 4% error-mamide, the total of glycolide and formamide ranging from 15% of the filler, and said watergla'ss constituent is selected from the group which consists oflsoaium s ilicatesolutions having a ratio of SiOz to NazO less than about 2.75 and a ratio of SiOz to H2O higher than about 0.35 and potassium silicate solutions having a ratio of SiOz to K20 less than about 2.25 and a ratio of SiO2 to H2O higher than about 0.35, the amount of said water-glass constituent ranging from about 25 cubic centimeters to about 30 cubic centimeters per grams of solid constituent present in said composition.

4. A self-hardening composition including a solid constituent and an aqueous water-glass constituent capable of yielding, upon hardening, a chemically-stable acid-resistant solid, wherein said solid constituent comprises quartz powder and 15% of glycolide, and said Water-glass constituent is selected from the group which consists of sodium silicate solutions having ratio of SiOz to NazO less than about 2.75 and a ratio of S102 to H2O higher than about 0.35, and potassium silicate solutions having ratio of $102 to K20 less than about 2.25 and a ratio of $102 to H2O higher than about 0.35, the amount of said waterglass constituent ranging from about 25 cubic centimeters to about 30 cubic centimeters per 100 grams of solid constituent present in said composition.

5. A self-hardening composition including a solid constituent and an aqueous water-glass constituent capable of yielding, upon hardening, a chemically-stable acid-resistant solid, wherein said solid constituent comprises graphite and l5% of glycolide, and said water-glass constituent is selected from the group which consists of sodium silicate solutions having a ratio of Si02 to NazO less than about 2.75 and a ratio of Si02 to H2O higher than about 0.35, and potassium silicate solutions having a ratio of Si02 to K20 less than about 2.25 and a ratio of S102 to H20 higher than about 0.35, the amount of said water-glass constituent ranging from about 25 cubic centimeters to about 30 cubic centimeters per 100 grams of solid constituent present in said com position.

6. A process for making an acid proof mass which comprises mixing an inert filler with from 1-5% of glycolide, and then cementing each 100 grams of said mixture with an amount from about 25 to about 30 cc. of at least one alkali- Waterglass solution of the group consisting of sodium silicate solutions having a ratio of S102 to Na2O less than about 2.75 and a ratio of SiOz to H2O higher than about 0.35, and of potassium silicate solutions having a ratio of SiO2 to K20 less than about 2.25 and a ratio of SiOz to H20 higher than about 0.35, and allowing the mass to harden by itself.

7. A process for making an acid proof mass which comprises mixing an inert filler with from 1-5% of glycolide and less than 4% of formamide, the total of glycolide and formamide ranging from 15% of the filler, and then cementing each 100 grams of said mixture with an amount from about 25 to about 30 cc. of at least one alkaliwaterglass solution of the group consisting of sodium silicate solutions having a ratio of Si02 to Na2O less than about 2.75 and a ratio of Si02 to H2O higher than about 0.35, and of potassium silicate solutions having a ratio of $102 t K20 less than about 2.25 and a ratio of S102 to H110 "Number higher than about 0.35, and allowing the mass to 2,206,046 harden by itself. 2,492,790

KARL DIETZ.

References Cited in the file of this patent 0 Number UNITED STATES PATENTS 13%,??? Number Name Date 72 :534 1,832,752 Thoretz Nov. 17, 1931 256,258 2,069,486 Tilden Feb. 2, 1937 551,403

Name Date Pollard July 2, 1940 Farkas Dec. 27, 1949 FOREIGN PATENTS Country Date Australia Sept. 28, 1939 Australia Sept. 28, 1939 Germany Aug. 6, 1942 Great Britain Mar. 10, 1927 Great Britain Feb. 22, 1943 

1. A SELF-HARDENING COMPOSITION INCLUDING A SOLID CONSITUENT AND AN AQUEOUS WATER-GLASS CONSTITUENT CAPABLE OF YIELDING, UPON HARDENING, A CHEMICALLY-STABLE ACID-RESISTANT SOLID, WHEREIN SAID SOLID CONSTITUENT COMPRISES AN INERT FILLER AND 1-5% OF GLYCOLIDE, AND SAID WATER-GLASS CONSTITUENT IS SELECTED FROM THE GROUP WHICH CONSISTS OF SODIUM SILICATE SOLUTIONS HAVING A RATIO OF SIO2 TO NA2O LESS THAN ABOUT 2.75 AND A RATIO OF SIO2 TO H2O HIGHER THAN ABOUT 0.35, AND POTASSIUM SILICATE SOLUTION HAVING A RATIO SIO2 TO K2O LESS THAN ABOUT 2.25 AND A RATIO OF SIO2 TO H2O HIGHER THAN ABOUT 0.35, THE AMOUNT OF SAID WATER-GLASS CONSTITUENT RANGING FROM ABOUT 25 CUBIC CENTIMETERS TO ABOUT 30 CUBIC CENTIMETERS PER 100 GRAMS OF SOLID CONSTITUENT PRESENT IN SAID COMPOSITION. 